one in a hundred
Manned space activities have strict requirements for astronauts' physiology and psychology. According to the space mission and its different requirements for all kinds of astronauts, space medical experts formulate corresponding selection items, contents and standards. Generally, it includes basic qualification examination, clinical medical examination, physiological function selection, psychological selection, endurance and adaptability selection of special environmental factors, etc. The selection criteria and conditions of astronauts in different countries are basically the same, especially the requirements for physical fitness are the same.
There are many similarities between the selection criteria and methods of early astronauts in the United States and the Soviet Union. Astronauts are all selected from fighter pilots; The selection of astronauts is based on the selection of pilots; The required selection items are similar. The ratio of selection and elimination is about 1: 100. The first batch of seven astronauts in project mercury were selected from 500 military pilots. The first batch of 20 astronauts in the Soviet Union were selected from more than 3,000 pilots, and then 8 of them were eliminated. In fact, only 12 people took part in this flight.
From a gender perspective, astronauts are mainly men. Nearly 20 years after the first female astronaut, valentina tereshkova, flew,1August, 982, Soyuz T-7 spacecraft and female astronaut Svetlana Savika (34 years old) flew for the second time. At present, the number of female astronauts is gradually increasing. In terms of age, drivers and mission experts are generally 22-40 years old, and load experts can be over 40 years old. Because the former Soviet Union used spacecraft as the transportation system between heaven and earth, the age requirements for astronauts were strict, and fewer astronauts continued to fly over 50 years old, while many astronauts in the US space shuttle were over 50 years old. In terms of height, the astronauts' height is generally below 170 cm due to the small space of the return cabin of the former Soviet Union Soyuz spacecraft, while the cabin space of the American space shuttle is relatively large, and the height range of space pilots is wide, ranging from 162.5- 193.0 cm.
In order to ensure that astronauts have excellent physical fitness, the choice of physiological function is extremely critical. Physiological function selection is mainly to select those who have excellent basic physiological functions in human organ systems. Physiological function selection includes cardiovascular and pulmonary function examination, central nervous system function examination, auditory function examination, visual function examination, endocrine and immune function examination, etc.
The psychological and mental state of astronauts has a great influence on the completion of space missions, especially for long-term flights and multi-person groups, the selection of their psychological quality is very important. Astronauts live in a harsh, closed and isolated environment, and they also face unpredictable risks in space. In this environment, it is impossible to complete the prescribed tasks without extraordinary "strong nerves".
Psychological selection methods include psychological investigation and psychological conversation, personality psychological test, intelligence and cognition, and psychomotor ability. For a multi-person crew, special attention should be paid to the adaptability and coordination of astronauts.
In the process of space flight, we will encounter various special environmental factors, such as overweight, weightlessness, low pressure, hypoxia, high and low temperature, vibration, noise, radiation, isolation and so on. In the process of selecting astronauts, we should eliminate those who are sensitive to these special environmental factors and have poor tolerance, and select those who have excellent endurance and adaptability.
Strict vestibular function selection is also an important link in astronaut selection, which can effectively reduce the incidence of space motion sickness under weightlessness.
Space motion sickness, also known as space sickness, is caused by the inadaptability of the human body in weightlessness, which is very similar to the usual motion sickness and seasickness of ordinary people. At first, it was epigastric discomfort, and then there was pallor, sweating, dizziness, dizziness, nausea and vomiting, but the symptoms would be obviously alleviated after vomiting. Space motion sickness usually appears when a manned spacecraft enters orbit, and the symptoms disappear automatically after 2 to 4 days. However, don't think that space motion sickness is not a big deal. In fact, it is a big problem that is difficult to overcome for the development of manned space flight and space life science.
Due to the high incidence of space motion sickness, according to the data, nearly half of astronauts will suffer from this disease after entering orbit. The schedule of manned flight is very strict, and astronauts need to complete many important operations during this period after they are in orbit. If motion sickness occurs at this time, it will more or less affect the completion of its space mission, and even affect the safety of manned space flight in serious cases. Secondly, the onset of motion sickness does not have certain regularity. Although people who take part in space flight for the first time will suffer from this disease, it will also happen to some astronauts who have been in the sky for many times, which will have an impact on the original flight plan.
Therefore, vestibular function is related to astronauts' work efficiency, physical health and flight safety. The experience of the United States and Russia proves that strict selection of vestibular function is one of the effective measures to reduce the incidence of space motion sickness. Generally, swivel chair, swing or temperature stimulation to ear organs are used to check the sensitivity and stability of vestibular organs.
Vestibular function
Vestibule is the main terminal sensory organ of human balance system, which grows in the petrous part of temporal bone of skull. People's ears are divided into outer ear, middle ear and inner ear (inner ear is also called lost), and vestibule is one of the organs of inner ear. The vestibule is responsible for sensing the spatial position of the human body. For example, even if you sit in a moving car and close your eyes and don't look out of the window, you can feel the acceleration, deceleration or turning of the car, which is what the vestibule perceives. As a sensory organ, vestibule will affect people's perception ability if it fails, thus causing dizziness. At present, 70% of vertigo cases are caused by the disharmony of vestibular system. As an astronaut, the vestibule will be directly impacted by the drastic changes in the environment, so the inspection of vestibule organs has become an important link in astronaut selection.
In the selection of astronauts, the ability of astronauts to withstand overload must also be tested. Overload is generally caused by acceleration or deceleration of spacecraft during launch and return. During the test, a centrifuge was used to measure the overweight endurance of the candidates in the horizontal direction (chest and back) and the vertical direction (head and basin direction). The overweight values of different manned spacecraft are different during flight. The overweight value of spacecraft is high, while the overweight value of space shuttle is small. Astronauts are usually required to have a longitudinal overweight endurance of not less than 3g, and a lateral overweight endurance of three times that of the longitudinal overweight endurance.
The atmospheric pressure in manned spacecraft cabin is due to the design consideration of pressure system (low pressure is selected), extravehicular decompression, pressure emergency, fire fighting and other situations that need decompression in extravehicular activities. There may be low pressure and low oxygen partial pressure, which requires astronauts to have certain tolerance to low pressure and low oxygen. During the selection, low pressure and anoxia should be checked, with the purpose of eliminating low pressure susceptibility and anoxia sensitive person. Generally, the low-pressure cabin is raised to a height of 5000 meters to check the sensitivity to hypoxia, and the low pressure and pressure change check the sensitivity to low pressure and pressure change.
In addition, the noise transmitted to the cabin during the launch and return of the spacecraft will be high, and the noise generated by the cabin equipment will also be encountered during the on-orbit flight. It is necessary to check the noise sensitivity of astronauts. Inspection is to test candidates with the noise frequency encountered in space flight and exclude those who have adverse reactions.
In manned space flight, different astronauts are responsible for different jobs. In the early days of manned flight, there is generally only one person flying, which is generally called a pilot. Later, it developed into a multi-person flight and was compiled into a crew. The crew is mainly composed of professional astronauts and sometimes non-professional astronauts. Each astronaut plays a different role in space flight and gradually develops towards specialization. The crew of both are generally commanders and pilots (the United States) or commanders and on-board engineers or research astronauts (the Soviet Union/Russia). Crew groups with more than three people are generally divided into commanders, pilots, mission experts and load experts (USA) or commanders, airborne engineers and research astronauts (USSR/Russia).
Take the American crew as an example, the commander, also known as the captain, is the leader and person in charge of a specific flight crew. In flight, he is responsible for arrangement, implementation, flight command, communication and flight safety, and sometimes serves as a pilot. Pilots are mainly responsible for monitoring, manipulating and controlling the flight of spacecraft, and for the inspection and maintenance of spacecraft. Assist the commander in his work. If the commander is unable to perform his duties, the driver has the right to take over the commander's work. Mission experts are required to receive comprehensive training in various spacecraft systems and load operations, and to be proficient in all mission implementation requirements and the purpose, requirements and operation management of load missions. Participate in mission planning and coordinate the relationship between all load experiments and spacecraft. The main task of the mission expert is to achieve the overall goal of the load experiment in the on-orbit flight phase according to the approved flight plan. The first three types of astronauts are all professional astronauts. PayloadSpecialist is a non-professional astronaut, who is the representative of the specific load customers on the spacecraft. Expertise in using and maintaining specific loads. Responsible for specific load operation in specific flight tasks, collect and process experimental data, maintain and repair load equipment, and contact the ground load control center.
With the development of manned space flight, astronauts are expanding into many different industries, such as scientists, engineers, doctors, teachers, journalists, politicians, managers and space tourists.
Astronauts are a special kind of people engaged in space activities. Under special environmental conditions, they have to complete special tasks such as flight monitoring, operation, control, communication, maintenance and scientific research inside and outside the spacecraft, and can lead a normal life. This requires strict training for them, so that they have excellent physical and psychological qualities, strong adaptability to special environmental factors in space, and are proficient in all kinds of knowledge and skills needed for spacecraft and mission completion.
The training contents of astronauts include: physical exercise, theoretical knowledge education, psychological training, endurance and adaptability training of special environmental factors, survival training and spacecraft technology training, aerospace medical engineering technology training, space science and applied knowledge and technology training, survival training and comprehensive training. According to the different categories and occupations of astronauts, the specific requirements and contents of their training are also different. Professional astronauts, such as pilots and mission experts, have more training contents, stricter requirements and longer training time, which generally takes about 3 years. Non-professional astronauts, such as load experts or scientists, have less training content and shorter training time.
Constitution and theory
As a basic condition for a person's survival, physical fitness is very important in the training process of astronauts. In order to prepare for the Apollo-Alliance plan, the Soviet Union required its astronauts to ride bicycles 1000 kilometers, ski for 3,000 kilometers and cross-country for more than 200 kilometers within one and a half years of training. In order to improve the endurance of astronauts, Houston Space Center once put on an 80-kilogram spacesuit and walked 30 kilometers a day in the hot Florida desert.
In addition to physical training, astronauts need to master a lot of theoretical knowledge in order to prepare for a flight, including basic space knowledge, mission and spacecraft structure, space medical engineering knowledge, space knowledge and application-related knowledge.